With this Puzzle I thee Kill by Parnell Hall

In ten words or less: Cora plans to wed again; Sherry's best friend marries Dennis.

Review: The many-times wed Cora Felton is planning to tie the knot again with the mysterious Raymond Harstein III. She's asked her niece Sherry to be her maid of honor. Sherry's best friend Brenda is getting married too, and has asked Sherry to stand up for her. But when Sherry discovers Brenda's finace is Sherry's abusive ex-husband Dennis, she wants nothing to do with the wedding. Threatening cryptograms arrive, warning Cora to cancel the wedding.

Why bother? Fans of the series will enjoy the opportunity to get to know one of Cora's husbands before he becomes an "ex."